Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

OCR Biology AS Level > 4.1 - Communicable Diseases > Flashcards

4.1 - Communicable Diseases Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

What is a Pathogen?

A

An (micro)organism that causes DISEASE.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is a Host?

A

The organism in which a pathogen lives inside.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the 4 types of pathogens?

A
  1. BACTERIA
  2. FUNGI
  3. VIRUS
  4. PROTOCTISTA
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Explain how bacteria can cause disease.

A

Bacteria can reproduce rapidly and release toxins or waste products that are toxic to the HOST.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What must you do when you are stating a causative agent of a pathogen (usually Latin)

A
  • Make sure it is UNDERLINED.
  • Make sure that the first letter is UPPERCASE.
  • Make sure that if you are on a computer, the name is in ITALIC.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

(Bacteria) Explain what Tuberculosis does.

State its causative agent.

A
  • A disease that affects mainly the lungs and kills cells and tissues.
  • “Mycobacterium tuberculosis” AND “M. bovis”
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

(Bacteria) Explain what Bacterial Meningitis does.

State its causative agent.

A
  • Infection of the MENINGES (the membranes that surround the brain and spinal cord). It makes them swollen and may cause damage to the brain and nerves.
  • Neisseria meningitidis OR Streptococcus pneumonia
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

(Bacterium) Explain what Ring Rot (in plants) does.

State its causative agent.

A
  • ring of decay in the VASCULAR TISSUE of a potato tuber or tomato, accompanied by leaf wilting.
  • Clavibacter michiganensis (subspecies: sepedonicus)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Explain how fungi can cause disease in ANIMALS.

A
  1. The fungi lives under the skin of the animal.
  2. They grow these thread-like fibres called HYPHAE.
  3. Lots of hyphae bundle up to make a network called a MCYELIUM.
  4. The fungus can send out specialised REPRODUCTIVE HYPHAE which grow to the surface of the skin to release SPORES.

This causes REDNESS and IRRITATION.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Explain how fungi can cause disease in PLANTS.

A
  1. The fungus often lives in the VASCULAR TISSUE, where it can gain NUTRIENTS.
  2. The hyphae release EXTRACELLULAR ENZYMES, e.g. cellulase, to DIGEST the surrounding tissue which causes DECAY.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

(Fungi) Explain what Black sigatoka (bananas) does.

State its causative agent.

A
  • causes leaf spots on banas plants, reducing yield.

- Mycosphaerella fijiensis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

(Fungi) Explain what Ringworm (cattle) does.

State its causative agent.

A
  • growth of fungus in a skin with spore cases erupting through skin to cause a rash.
  • Trichophyton verrucosum
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

(Fungi) Explain what Athlete’s foot (humans) does.

State its causative agent.

A
  • growth under skin of FEET (particularly between the toes)

- Trichphyton rubrum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Explain how viruses cause disease.

A
  1. invades cells and take over the genetic machinery and organelles of the cell.
  2. they cause the cell to manufacture more copies of the virus.
  3. the host cell BURSTS, releasing more and more viruses which infect the healthy cells.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

(Virus) Explain what HIV/AIDS does.

State its causative agent.

A
  • attacks cells in the immune system and compromises the immune response.
  • Human Immunodeficiency Virus (HIV)

NOTE: AIDS is CAUSED by HIV. AIDS isn’t a virus itself.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

(Virus) Explain what influenza does.

State its causative agent.

A
  • attacks respiratory system and causes muscle pains and headaches.
  • from the family Orthomyxoviridae (‘flu’ viruses)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

(Virus) Explain what the tobacco mosaic virus does.

State its causative agent.

A
  • causes mottling and discolouration of leaves

- tobbaco mosaic virus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Explain how Protoctista causes disease.

A

They cause harm by entering host cells and feeding on the contents as they grow.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

(Protoctistan) Explain what Blight (tomatoes and potatoes) does.
State its causative agent.

A
  • affects both leaves and potato tubers

- Phytophthora infestans

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

(Protoctistan) Explain what Malaria does.

State its causative agent.

A
  • parasite in the blood that causes headache and fever and may progress to coma and death
  • Plasmodium falciparum, P. vivax, P. ovale, P. malariae
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Define “DIRECT TRANSMISSION”.

A

Passing a pathogen from host to new host, with no intermediary.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Explain how DIRECT PHYSICAL CONTACT arises.

A
  • i.e. touching a person who is infected or touching contaminated surfaces (e.g. soil) that harbour the pathogens.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

State 4 diseases associated with “Direct Physical Contact”.

A
  1. HIV
  2. Bacterial Meningitis
  3. Ringworm
  4. Athlete’s Foot
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What are the factors that affect “Direct Physcal Contact” transmission (i.e. how can you prevent it from happening?)

A

Hygiene - wash your hands regularly, esp. after using the toilet, keep surfaces clean, sterilising surgical instruments, etc.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Explain how “FAECAL-ORAL TRANSMISSION” arises.

A

Usually by eating food or drinking water contaminated by the pathogen.

26
Q

State 2 diseases associated with “Faecal-oral Transmission”.

A
  1. Cholera

2. Food poisoning

27
Q

What are the factors that affect “Faecal-oral” transmission (i.e. how can you prevent it from happening?)

A
  • using human sewage to fertilise the crops is a big factor/issue.
  • correct treatment of water is vital to prevent from happening
  • careful preparation with food and drink.
28
Q

Explain how “DROPLET INFECTION” arises.

A

-the pathogen is carried in tiny water droplets in the air.

29
Q

State 2 diseases associated with “Droplet Infection”.

A
  1. Tuberculosis

2. Influenza

30
Q

What are the factors that affect “Droplet Infection” transmission? (i.e. how can you prevent it from happening?)

A

CATCH IT. BIN IT. KILL IT.
Cover your mouth when sneezing or coughing.
Use a tissue and make sure that it’s disposed of correctly.

31
Q

Explain how “TRANSMISSION BY SPORES” arises.

A

Spores can be carried in the air or reside on surfaces or in the soil.

32
Q

State 2 diseases associated with “Transmission by Spores”.

A
  1. Anthrax

2. Tetanus

33
Q

What are the factors that affect “Transmission By Spores”? (i.e. how can you prevent it from happening?)

A

Use of a MASK.

Washing skin after contact with soil.

34
Q

What other SOCIAL factors affect transmission (6)?

A
  1. OVERCROWDING
  2. POOR VENTILATION
  3. POOR HEALTH (especially if the person has HIV/AIDS)
  4. POOR DIET
  5. HOMELESSNESS
  6. Living or working with people who have MIGRATED FROM DISEASE-DENSE AREAS.
35
Q

Define INDIRECT transmission.

A

Passing a pathogen from host to new host; VIA A VECTOR.

36
Q

Define a VECTOR.

A

An organism that CARRIES a pathogen from one host to another.

37
Q

Explain how the INDIRECT transmission of MALARIA works (hint: it’s a cycle).

A
  1. A person with malaria has the GAMETES of Plasmodium in their blood.
  2. The female Anopheles mosquito SUCKS BLOOD.
  3. Plasmodium develops and migrates to the mosquito’s SALIVARY GLANDS.
  4. An uninfected person is BITTEN.
  5. Plasmodium migrates to LIVER.
  6. Plasmodium migrates to BLOOD.
38
Q

Give 3 examples of DIRECT transmission in PLANTS.

A
  1. in SOIL (normally DAMAGED roots)
  2. SPORES (normally AIRBORNE)
  3. FRUIT/SEEDS (dangerous as it can affect the next generation of plants)
39
Q

Explain how a pathogen infects a plant and explain how it can infect ANOTHER plant.

A

It attacks the VASCULAR TISSUE, and the pathogens in the leaves are distributed when the leaves are SHED.

So the pathogen is carried back into the soil where it can attack another plant.

40
Q

Explain how INDIRECT transmission arises in PLANTS.

A

Insect Attack: The spores or bacteria become attached to a burrowing insect, e.g. a beetle, which attacks an infected plant.

When that beetle attacks another plant, the pathogen is transmitted to the uninfected plant.

41
Q

Why is there a great variety of diseases in warmer climates?

A

Many protoctists, bacteria and fungi can reproduce more rapidly in warm and moist conditions.

42
Q

What is a memory tip that you can use to remember the different examples of passive physical defenses in PLANTS?

A

LST CW BC (sounds like LOST COW BACK)

43
Q

What does the “L” stand for in “LST CW BC” and how does it provide a barrier to pathogens?

A

Lignin thickening of cell walls - lignin is WATERPROOF and almost competely INDIGESTIBLE.

44
Q

What does the “S” stand for in “LST CW BC” and how does it provide a barrier to pathogens?

A

Stomatal closure - When pathogenic organisms are detected, the guard cells will close the stomata in that part of the plant.

45
Q

What does the “T” stand for in “LST CW BC” and how does it provide a barrier to pathogens?

A

Tylose formation - Tylose is a balloon-like swelling that BLOCKS xylem vessels so that pathogens can’t enter.

46
Q

What does the “C” stand for in “LST CW BC” and how does it provide a barrier to pathogens?

A

Cell wall - physical barrier with chemical defenses

47
Q

What does the “W” stand for in “LST CW BC” and how does it provide a barrier to pathogens?

A

Waxy cuticles - stops water from collecting (so the pathogen can’t survive since it needs water).

48
Q

What does the “B” stand for in “LST CW BC” and how does it provide a barrier to pathogens?

A

Bark - contains chemical defenses.

49
Q

What does the second “C” stand for in “LST CW BC” and how does it provide a barriet to pathogens?

A

CALLOSE - a POLYSACCHARIDE deposit that BLOCKS old phloem sieve tubes.

50
Q

What are the 5 examples of chemicals used in the plant chemical defences?

A

T H-PAD

  1. Terpenoids
  2. Hydrolytic Enzymes
  3. Phenols
  4. Alkaloids
  5. Defensive proteins (defensins)
51
Q

Explain what Terpenes in Tyloses (TERPENOIDS) are.

A

Oils with antibacterial and antifungal properties.

52
Q

Explain what Tannins in Bark (PHENOLS) are.

A
  • They inhibit attacks by insects.
  • Binds to enzymes in the insect saliva and digestive system.
  • Deactivates them
  • Can be lethal in high doses, preventing transmission.
53
Q

Why are the chemicals used in chemical defences known as ACTIVE defences?

A

The chemicals produced require A LOT OF ENERGY.

54
Q

When are Active Defenses produced?

A

When the pathogens ATTACK

think of it like soldiers attacking a fortress

55
Q

How does the plant know a pathogen is attacking?

A

It detects the chemicals in the pathogen’s cell wall. This fortifies the defences already present.

56
Q

Which physical defences are fortified when a pathogen is attacking?

A
  1. CELL WALLS (thickened and strengthened with additional cellulose)
  2. CALLOSE (deposited between the plant cell wall and membrane and BLOCKS plasmodesmata which are cytoplasmic bridges between cells where pathogen is present)
  3. NECROSIS (delibirate cell suicide): A few cells are sacrificed and creates a barrier of dead cells which limits the pathogen’s access of water and nutrients. (activated by intracellular enzymes and in turn activated by injury)
  4. CANKER: sunken necrotic lesion in the woody tissue, causes death of CAMBIUM TISSUE.
57
Q

Explain what ALKALOIDS are.

A
  • e.g. caffeine, nicotine, morphine, cocaine, solaine
  • gives the plant a BITTER TASTE.
  • some INHIBIT ENZYMES.
  • limits GRAZING.
58
Q

Explain what DEFENSE PROTEINS (defensins) are.

A
  • small, cysteine-rich proteins that have broad anti-microbial activity.
  • possibly inhibit the action of ion-transport channels.
59
Q

Explain what HYDROLYTIC ENZYMES are.

A
  • e.g. chitinases, glucanases, lysozymes.

- breaks down pathogenic cell walls.

60
Q

Explain what an OXIDATIVE BURST is.

A
  • produces highly reactive oxygen molecules capable of damaging the cells of invading organisms.
61
Q

What are Primary Defences?

A

Those that prevent pathogens entering the body.

OCR Biology AS Level (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions